Chair frame



FIG. 1 is a side perspective view of a chair frame showing my new design;

FIG. 2 is a right side elevational view, the left side being a mirror image thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof; and,

FIG. 5 is a top plan view thereof. 

The ornamental design for a chair frame, as shown and described. 